Users often have multiple accounts that contain a variety of values. The values can be debit values or credit values, can be of different currencies and even contain non-currency values. Transferring values from one account to another account has often entailed significant complexity involving account numbers, routing numbers, passwords, etc. Further, it often has been a challenge to identify which account is which and whether the accounts were set up to send and receive value.
Even if the accounts were set up for transfers, the physical mechanism for making the transfer was difficult.